A Panorama about the owners of the Daily Telegraph, Sir David and Sir Frederick Barclay, that had been deferred by former BBC director general George Entwistle, is now back on following the departure of the broadcasting chief who had reservations about whether to broadcast the investigative documentary.

The programme, being fronted by journalist John Sweeney, about the reclusive - and often litigious - billionaire twins, was referred up to the embattled director general last week and was effectively put on hold. It had been previously approved by other senior news executives, but such were the sensitivities that this film was sent right up to the top.

Sweeney said that reports in other newspapers that the Panorama had been pulled were "not true" and that he and the production team "were still working on it, and we hope to put it out soon". No broadcast date has been agreed, but the BBC usually chooses the last possible moment to confirm what is airing on Panorama each week.

It is not clear precisely what the subject of the programme will be, although another BBC source said that it would be piece of investigative journalism, because Panorama was "not a soft toy factory". But there are some clues emerging elsewhere.

Panorama's filming has already attracted the ire of the man who manages the Barclay's estate on Sark, the channel island, which Brecqhou, the neighbouring island where the twins live, is legally part of. Kevin Delaney, who runs the twins Sark Estate Management, wrote a lengthy article criticising the BBC in his Sark Newsletter.

Writing on October 22, Delaney accused the BBC of being "a deeply flawed and dysfunctional organisation that has failed miserably in its self-regulation". He said that Sweeney had visited Sark on three occasions in the autumn, and after accusing the BBC journalist of "unbecoming drunken antics at the pub" - he complained about his investigation.

"Empowered by the might of the BBC, Mr Sweeney filmed people without their consent. He aggressively invaded my offices and harassed and intimidated my staff in his concerted efforts at staging a hostile confrontation with me on camera - despite being made aware, in writing, that I did not want to be interviewed by him," Delaney wrote.

Delaney added that he had made a complaint to George Entwistle, and other BBC executives, which he said had been ignored or not acknowledged. He said that the production team's behaviour meant that "the British licence payers' money was thus spent to support a campaign to shut down free speech on Sark".

John Sweeney had previously been sued by the Barclay twins in the 1990s after he was filmed landing on their island of Brecqhou, which is next to the channel island of Sark. Both the journalist, and John Birt, the then director general, were sued by the twins in France - and after a lengthy legal action, Sweeney was ordered to pay 20,000 Francs in damages by a court in Rennes.